In general, in order to charge a terminal device, such as a mobile phone, a notebook, etc., the terminal device needs to be directly connected to a charger, or be connected to the charger through a USB charging cable.
The above-described wired charging method restricts a scope of application of the portable terminal device, and thus a requirement for technology allowing a user to charge a terminal wirelessly at any place is being increased according to recent development of information communication devices, such as smart phones, etc.
FIG. 1 is a view illustrating the concept of general wireless charging.
As shown in FIG. 1, a general wireless charging system may include an electromagnetic generator 200 and a terminal 100.
The electromagnetic generator 200 generates radio waves allowing the terminal 100 to generate induced current. The terminal 100 having received such radio waves may include an induced current generation unit to generate induced current through the received radio waves and a battery charging unit. Such an induced current generation unit may generate induced current using the radio waves generated from the electromagnetic generator 200, and charge a battery through the induced current.
However, the above-described basic concept of wireless charging relates to a case in which the electromagnetic generator 200 is operated as a device generating only radio waves for wireless charging. Therefore, investigation of a more flexible wireless charging method using general base stations (e.g., macro BSs) as well as access points (APs), Femto base stations (BSs), relay stations and wireless personal area networks (WPANs) is required.